1. Technical Field
The present disclosure relates to a method for manufacturing a semiconductor element.
2. Description of Related Art
Semiconductor elements such as light emitting diodes (LEDs) are produced by epitaxially growing a semiconductor layer on a substrate and then separating the resulting wafer into individual elements. Examples of how the wafer is separated into individual elements include the use of a dicer, a scriber, and a laser scriber. A sapphire substrate is typically used as the substrate when a nitride semiconductor is used for the semiconductor layer.
One method that has been proposed for dividing up elements having the sapphire substrate involves using a short-pulse laser (femtoseconds (fsec) or picoseconds (psec)) to emit a laser beam from the rear side of the sapphire substrate to produce a modified region in the interior of the substrate, produce cracks or the like from the modified region, and split along these lines. Sometimes, due to the fact that the sapphire substrate is thick or another such reason, the laser that forms the modified region may not cut sufficiently with a single scanning pass. Methods that have been proposed to avoid this problem are a method in which the laser scanning is performed a number of times at different depths to provide a plurality of rows of modified regions (for examples, see Japanese Unexamined Patent Application Publication Nos. 2008-98465 and 2002-205180), and a method in which a plurality of rows of modified regions are made to overlap each other (for examples, see Japanese Unexamined Patent Application Publication No. 2014-36062).